examples/vhost: remove unnecessary pseudo checksum calculation
examples/vhost: remove unnecessary pseudo checksum calculation

For checksum offloading only case, the TCP/IP stack would
have calculated the pseudo checksum. Therefore, we don't
need to re-calculate it again here; remove it.

Signed-off-by: Yuanhan Liu <5dcef21195e64c9c08aa779bb62b25e9133eaa33@linux.intel.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk